1. Field of the Invention
The present invention relates to diffusion transfer processors and more particularly to a sheet separator permitting accurate registration of a light sensitive sheet of film or paper having an image exposed upon it (hereinafter called "negative sheet") and a non-sensitive image receiving sheet of film or paper (hereinafter called "receiver sheet") prior to, during and after being processed.
A diffusion transfer processor transfers a graphic image from an exposed negative sheet to a receiver sheet by passing the superposed negative sheet and receiver sheet through a bath of chemical activator or developer in which the negative sheet and receiver sheet are temporarily separated one from the other as they move through a tray containing the chemical bath and are rejoined in face to face contiguous contact by a pair of squeegee rollers retaining excess activator within the tray.
Conventional diffusion transfer processing units do not provide for pin registration of the negative sheet with the receiving sheet while the negative sheet and receiving sheet are being processed for the reason the negative sheet and receiving sheet must be disposed on the respective upper and lower surfaces of a planar separator when entering the chemical bath to insure contiguous coating of the chemical activator on the emulsion face surface of the negative sheet and receiver sheet. It is desirable when preparing graphic images, to be later reproduced for printing, to register a plurality of supplemental images on a plurality of receiving sheets from which printing plates can be exposed in register for color printing in different colors, or the like. This invention provides a negative sheet and receiver sheet separator permitting such registration.
2. Description of the Prior Art
Diffusion transfer processor units presently used comprise a table top unit including a tray containing a bath of chemical activator into which one edge of a negative sheet and receiver sheet are manually inserted on respective upper and lower surfaces of a planar separator. At least one pair of negative sheet and receiver sheet advancing rollers, driven by an electric motor, advances the negative sheet and receiver sheet through the activator bath. The planar separator, being at least coextensive with the negative and receiver sheet widths, prevents pin registration of the negative sheet with the receiver sheet while being processed by the apparatus. At least one conventional diffusion transfer processor provides a negative sheet and receiver sheet horizontal shelf adjacent the entrance opening supported by the shelf to permit alignment of one edge surface of the respective negative sheet and receiver sheet but does not permit repeated accurate registration of the negative sheets and receiver sheets while passing through the processor.